Cheap cardboard freezer boxes?

We just set out to order more cardboard freezer boxes (5.25 x 5.25 x 2
in.). The ones we've been getting are around $3.60/box (including dividers
for 81 tubes). My attempts to find cheaper ones have been fruitless. You
can find cheaper boxes (~$2.00) but they don't include dividers. When you
add those in, the price is about the same as what we've been paying. Does
anyone know of a cheaper source, or a cheap alternative?
Thanks, Todd
--
Dr. Todd Richmond
Carnegie Institution of Washington
260 Panama Street Email: todd at andrew2.stanford.edu
Stanford, CA 94305 Homepage: http://cellwall.stanford.edu/todd